will define two mappings: <leader>t which will call command :Bar and
<leader>T which will run s:F.baz function. Both mappings are silent. Now
pretend that you are the user who does not need to run s:F.baz and wants to
launch :Bar using ,t. In this case all he needs is to add the following
lines to the vimrc:

If you don't want to prefix your options with foo (second component after
runtimepath of a path to your plugin), define s:_oprefix. Note the
checker key: it saves you from writing code for checking user input (but
will instead generate an exception for invalid value).